Operator Overloading

[badkaykay]

Here is my question. How do I know if this function is to be global or a member? I made it a member function. I have been looking around online trying to find out how best to decide when you make a function global vs member function. If this function is supposed to be a member function, then I can't pass numCards directly because it is private not to mention, it can't access private data directly. I have read the operator overloading information here on this site, but am new on overloading operators.

EDIT: Found some answers in my book!